Australian scientists have discovered a cluster of brilliant shallow-water corals that could help in the search for anti-cancer drugs and to understand global warming.

The vividly fluorescent cluster was found in waters off Lord Howe Island, 600 kilometres east of the Australian mainland, with some displaying rich reds that were difficult to find and in high demand for studies of cancer cells, says researcher Dr Anya Salih.

"The underwater buttresses and caverns are densely inhabited by hundreds of corals, all deeply pigmented by the most intense green, blue and many with red fluorescence," she says.

Salih says she had never seen such an abundance of highly red fluorescent corals, nor such an extraordinarily vibrant site.

"We are using these pigments to light up the workings of living cells and to study what goes wrong in cancer cells," says Salih, from the University of Western Sydney.

The gene producing the particular pigment - red, green, blue or yellow - would be attached to a molecule in both healthy and cancerous cells, and would enable scientists to track cell growth and change using a special fluorescent-sensitive laser microscope.

Red pigments

Salih is working with scientists from the University of California to explore how cancer cells differ from normal cells and how effective anti-cancer drugs are. She says red pigments were especially valuable because they allowed researchers to see deeper into tissues.

The corals were discovered by scientists tracking the recovery of coral bleaching linked to global warming at Lord Howe Island. Salih says they are invaluable not only for her research, but for understanding climate change.

"Earlier this year, the coral reefs of Lord Howe Island experienced a sudden mass bleaching event caused by warming of seawater. It's a sign that global warming is beginning to be a threat to coral survival even to the most southern reefs in Australia," she says.

But the fluorescent corals had been much less damaged by the bleaching, lending "support to the hypothesis that fluorescence can provide some level of protection to corals from temperature stresses due to climate change."

"Coral fluorescence is proving to be incredibly important in the biology of coral reefs and their ability to survive stressful conditions," she says.